import java.util.Scanner;

public class Cha {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextLine()) {
            String str = sc.nextLine();
            System.out.println(fun(str));
        }
    }
    public static String fun(String str) {
        StringBuffer sb = new StringBuffer();
        int[] flg = new int[127];//默认都为0
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (flg[ch] == 0) {
                sb.append(ch);
                flg[ch] = 1;
            }
        }
        return sb.toString();
    }
}
